Compressor and chiller system including a compressor

ABSTRACT

A compressor and a chiller system including a compressor are provided. The compressor may include one or more impellers that draws a refrigerant in an axial direction and compresses the refrigerant in a radial direction, a rotating shaft that rotates the one or more impellers, and at least one displacement sensor that detects a displacement of the rotating shaft. The displacement sensor may include a flexible circuit board and coils provided on both sides of the flexible circuit board. The flexible circuit board may include a plurality of boards which may be connected to each other by one or more connectors.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Korean Patent Application No. 10-2015-0091067, filed in Korea on Jun. 26, 2015, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND

Field

A compressor and a chiller system including compressor are disclosed herein.

A conventional chiller system, which is a cooling apparatus adapted to supply cold water to cold water-demanding equipment, such as an air conditioner or a freezing machine, for example, is constructed such that refrigerant is circulated through a compressor, a condenser, an expansion valve, and an evaporator. The evaporator of the chiller system, which is a water-refrigerant type heat exchanger, is constructed to exchange heat between a refrigerant flowing through the evaporator and cold water, which has exchanged heat with a heat exchanger in an air conditioner or a freezing machine so as to cool the cold water. The condenser of the chiller system, which is a water-refrigerant type heat exchanger, is constructed to exchange heat between a refrigerant flowing through the condenser and cooling water, which has exchanged heat with a water cooling device, so as to cool the refrigerant.

The compressor of the chiller system is constructed to compress refrigerant and to supply the compressed refrigerant to the condenser. The compressor may include an impeller that compresses the refrigerant, a rotating shaft connected to the impeller, and a motor that rotates the rotating shaft. The rotating shaft is configured to be rotated in a bearing housing. When the rotating shaft is rotated in a state of being deviated from a predetermined position in the bearing housing, that is, a center of the bearing housing, various problems, such as noise generation decreased compressor efficiency, and breakage of the compressor, may occur.

Accordingly, in order to control the position of the rotating shaft in the bearing housing, there is a need for a displacement sensor that detects the position of the rotating shaft. Increasing a sensitivity of the displacement sensor enables the position of the rotating shaft to be more accurately controlled. Although a measure of increasing a number of turns of a coil, that is, the number of times the coil is wound may be considered in order to increase the sensitivity of the displacement sensor, there is a limit to increasing the number of turns of the coil in a circuit board having a certain size.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

FIG. 1 is a schematic diagram of a chiller system according to an embodiment;

FIG. 2 is a schematic diagram of a compressor provided in the chiller system shown in FIG. 1;

FIG. 3 is a schematic view showing a displacement sensor provided in the chiller system shown in FIG. 1;

FIG. 4 is a schematic cross-sectional view showing the displacement sensor shown in FIG. 3, which is coupled to a ferrite core;

FIG. 5 is a schematic plan view showing a flexible circuit board of the displacement sensor shown in FIG. 3, which has been developed;

FIG. 6 is a schematic cross-sectional view showing the displacement sensor shown in FIG. 3, which is mounted on a bearing housing of the compressor; and

FIG. 7 is a block diagram showing a connection relationship between components of the chiller system according to an embodiment.

DETAILED DESCRIPTION

Hereinafter, a compressor and a chiller system including a compressor according to embodiments will be described in detail with reference to the accompanying drawings. The accompanying drawings are provided only to illustrate an exemplary construction, and a technical scope should not be construed as being limited by the drawings.

The same or similar elements may be assigned the same or similar reference numerals, and redundant description thereof omitted. For clarity of description, shapes and sizes of components in the drawings may be exaggerated or scaled down. Although the terms “first”, “second”, etc. may be used herein to describe various elements, these elements should not be limited by these terms, and these terms are only used to distinguish one element from another.

FIG. 1 is a schematic view of a chiller system according to an embodiment. Referring to FIG. 1, the chiller system 1 according to an embodiment may include a compressor 10 that compresses a refrigerant, a condenser 20 that exchanges heat between the refrigerant, compressed by the compressor 10, and cooling water so as to condense the refrigerant, an expansion valve 30 that expands the refrigerant, which has been condensed by the condenser 20, and an evaporator 40 that exchanges heat between the refrigerant, which has been expanded, and cold water to evaporate the refrigerant, thereby cooling the cold water. The chiller system 1 according to an embodiment may further include an air-conditioning unit or air-conditioner 50 that exchanges heat between the cold water, which may be cooled at the evaporator 40, and air an air-conditioning space, thereby cooling the air in the air-conditioning space, and a cooling unit or cooler 60 that cools the cooling water, which has exchanged heat with the refrigerant in the condenser 20.

The condenser 20 may release the heat in the refrigerant, which has been compressed by the compressor 10, toward the cooling water so as to condense the refrigerant. In other words, in order to condense the refrigerant the condenser 20 may be configured to exchange heat between the cooling water supplied from the cooler 60 and the refrigerant supplied through the compressor 10.

For example, the condenser 20 may be a shell-tube type heat exchanger. In this case, the shell of the condenser 20 may be provided therein with a condensation space 210. The condensation space 210 may be provided therein with cooling water tubes 220, through which cooling water may flow. The cooling water tubes 220 may be connected to a cooling water introduction pipe 610 and a cooling water discharge pipe 620 of the cooler 60 so as to allow cooling water to flow therethrough.

The cooler 60 may cool the cooling water which has absorbed heat from the refrigerant in the condenser 20. The cooler 60 may include the cooling water introduction pipe 610, through which the cooling water may be introduced and the cooling water discharge pipe 620, through which the cooling water may be discharged. For example, the cooler 60 may be a cooling tower adapted to air-cool the cooling water which has absorbed heat from the refrigerant in the condenser 20.

The cooler 60 may include a body 630 including an air outlet 631 formed in an upper portion thereof, and an air inlet 632 formed in lateral side surfaces thereof, a blower fan (not shown), which may be provided at the air outlet 631 so as to forcibly draw external air into the body 630 and forcibly discharge the external air through the air outlet 631, a cooling water introduction pipe (not shown), which may be provided at an upper level in the body 630 so as to spray the cooling water, which has exchanged heat in the condenser 20, toward a lower position in the body 630, and a cooling water collector that collects cooling water, which has been sprayed from the cooling water introduction pipe and has been cooled by heat exchange with external air.

The evaporator 40 may supply heat to refrigerant, which has been expanded at the expansion valve 30, so as to evaporate the refrigerant. In other words, the evaporator 40 may be configured to exchange heat between cold water supplied from the air-conditioner 50 and the refrigerant so as to evaporate the refrigerant.

For example, the evaporator 40 may be a shell-tube type heat exchanger. In this case, a shell of the evaporator 40 may be provided therein with an evaporation space 410 in which refrigerant may be evaporated. The evaporation space 410 may be provided therein with cold water tubes 420 through which cold water may flow. The cold water tubes 420 may be connected to a cold water introduction pipe 510 and a cold water discharge pipe 520, which may be connected to the air-conditioner 50, so as to allow cold water to flow therethrough. The refrigerant, which has been evaporated in the evaporator 40, may be drawn into an introduction pipe 70 and may be compressed by the compressor 10.

The air-conditioner 50 may include a heat exchanger (not shown), which may supply heat to the refrigerant in the evaporator 40 so as to exchange heat between cold water and the air in the air-conditioning space, the cold introduction pipe 510, through which cold water may flow into the air-conditioner 50 from the evaporator 40, and the cold water discharge pipe 520, through which cold water may be discharged into the evaporator 40 from the cold introduction pipe 510 and the air-conditioner 50.

The compressor 10 may compress the refrigerant which has been evaporated in the evaporator 40. For example, the compressor 10 may be a turbo compressor. Further, the compressor 10 may be a single-stage compressor or a multistage compressor.

Hereinafter, a construction of the compressor 10 will be described in detail with reference to drawings.

FIG. 2 is a schematic diagram of a compressor provided in the chiller system shown, in FIG. 1. Referring to FIG. 2 in conjunction with FIG. 1, the compressor 10 according to an embodiment may include at least one impeller 110, which may serve to draw refrigerant, which has been evaporated in the evaporator 40, in an axial direction and to centrifugally compress the refrigerant, a rotating shaft 120 that transmits a rotational force to the impeller 110, a motor 130 that rotates the rotating shaft 120, and a bearing housing 140 that supports the rotating shaft 120.

The at least one impeller 110 may be configured to draw the refrigerant in the axial direction and to centrifugally compress the refrigerant. The refrigerant, which is compressed by the at least one impeller 100, may be supplied to the condenser 20.

The motor 130 may provide a drive force required to rotate the at least one impeller 110. The drive force from the motor 130 may be transmitted to the at least one impeller 110 through the rotating shaft 120.

The bearing, housing 140 may support the rotating shaft 120. For example, the bearing housing 130 may be configured to surround at least a portion of the rotating shaft 120.

The bearing housing 140 may be provided with one or more magnetic bearings 141 and 142. For example, the magnetic bearings 141 and 142 may be provided at two opposite, ends of the bearing housing 140 in a longitudinal direction. In other words, the magnetic bearings 141 and 142 may be mounted in the bearing housing 140 in front of and behind the motor 130. For the convenience of explanation, the magnetic bearing disposed or provided in front of the motor 130, may be referred to as a front magnetic bearing 141, and the magnetic bearing disposed or provided behind the motor 130, may be referred to as a rear magnetic bearing 142.

Each of the front magnetic bearing 141 and the rear magnetic bearing 142 may include a plurality of magnetic bearings. For example, the front magnetic bearing 141 may include two pairs of magnetic bearings, which may be disposed or provided in a cruciform shape, such that the two magnetic bearings in each pair thereof face each other with the rotating shaft 120 disposed or provided therebetween. The rear magnetic bearing 142 may also include two pairs of magnetic bearings, which may be disposed or provided in a cruciform shape, such that the two magnetic bearings in each pair thereof face each other with the rotating shaft 120 disposed or provided therebetween.

The magnetic bearings 141 and 142 may be controlled by a controller, which will be described hereinafter. More specifically, the controller may control the magnetic bearings 141 and 142 such that the rotating shaft 120 is disposed or provided at a predetermined position in the bearing housing 140. As positional control of the rotating shaft 120 through control of current or voltage supplied to the magnetic bearings 141 and 142 is well known in the art, a detailed description thereof has been omitted.

The bearing housing 140 may be provided with one or more displacement sensors 81 and 82. The one or more displacement sensors 81 and 82 may be positioned closer or adjacent to the magnetic bearings 141 and 142. For example, the displacement sensors 81 and 82 may be provided in the bearing housing 140 so as to be positioned in front of or behind the magnetic bearings 141 and 142. More specifically, the displacement sensors 81 and 82 may be provided in front of the front magnetic bearing 141 and behind the rear magnetic bearing 142. For the convenience of explanation, the displacement sensor disposed or provided in front of the front magnetic bearing 141, may be referred to as a front displacement sensor 81, and the displacement sensor disposed or provided behind the rear magnetic bearing 142 may be referred to as a rear displacement sensor 82.

The displacement sensors 81 and 82 may be provided in a same number as the magnetic bearings 141 and 142. For example, the front displacement, sensor 81 may include two pairs of displacement sensors, which may be disposed or provided in a cruciform shape, such that the two displacement sensors in each pair thereof face each other with the rotating shaft 120 disposed or provided therebetween. The rear displacement sensor 82 may also include two pairs of displacement sensors, which may be disposed or provided in a cruciform shape, such that the two displacement sensors in each pair thereof face each other with the rotating shaft 120 disposed or provided therebetween.

The displacement sensors 81 and 82 may detect displacement of the rotating shaft 120. More specifically, the displacement sensors 81 and 82 may be configured to detect a radial displacement of the rotating shaft 120, which is disposed or provided in the bearing housing 140. In other words, each of the displacement sensors 81 and 82 may include a plurality of displacement sensors, which may be disposed or provided around the rotating shaft 120 so as to be spaced radially apart from the rotating shaft 120. Accordingly, if the displacement sensors 81 and 82 are highly sensitive, it is possible to implement precise positional control of the rotating shaft 120.

In order to increase a sensitivity of the displacement sensors 81 and 82 it may be considered to increase a number of turns of coils provided in the displacement sensors 81 and 82, that is, the number of times the coil is wound. However, there is a limit to increasing the number of turns of the coil provided on a circuit board having a confined or limited size.

Hereinafter, a specific construction of the displacement sensors 81 and 82 which is intended to increase the sensitivity of the displacement sensors 81 and 82, will be described with reference to the drawings.

FIG. 3 is a schematic view showing a displacement sensor provided in the chiller system shown in FIG. 1. FIG. 4 is a schematic view showing the displacement sensor shown in FIG. 3, which is coupled to a ferrite core.

Referring to FIGS. 3 and 4, each of the displacement sensors 81 and 82 according to an embodiment may include a circuit board 810, and coils 820 disposed or provided on both sides of the circuit board 810. The circuit board 810 may be a flexible circuit board. The circuit board 810 may include a plurality of boards 811 to 815, which may be connected to each other via one or more connectors 830.

The one or more connectors 830 and the plurality of boards 811 to 815 may be integrally formed with each other. All of the one or more connectors 830 and the plurality of boards 811 to 815 may be made of a flexible material. In other words, all of the one or more connectors 830 and the plurality of boards 811 to 815 may serve as flexible circuit boards.

The plurality of boards 811 to 815 may be stacked in a zigzag manner by bending the one or more connectors 830. In other words, the plurality of the boards 811 to 815 may be stacked such that an upper side of one board faces a lower side of an adjacent board.

Each of the displacement sensors 81 and 82 may further include a ferrite core 840, to which the plurality of boards 811 to 815 may be coupled. Each of the plurality of boards 811 to 815 may have a coupling hole 816 formed in the center thereof, and the ferrite core 840 may include a coupling protrusion 846 corresponding to the coupling hole 816.

The ferrite core 840 may further be provided with a recess 841, in which the plurality of boards 811 to 815 may be mounted. For example, each of the plurality of boards 811 to 815 may have an annular shape, and the recess 841 may have a shape corresponding to a shape of the stacked boards 811 to 815.

The ferrite core 840 may be entirely made of a ferrite material. Alternatively, it is also possible for only the coupling protrusion 846 of the ferrite core 840 to be made of a ferrite material. The ferrite core 840 may serve to increase an inductance of the coil 820 and to increase an accuracy of the displacement sensors 81 and 82.

As each of the plurality of boards 811 to 815 is provided at both sides thereof with the respective coils 820, there is a concern that the coils disposed or provided on adjacent boards will contact each other, thereby causing electrical short. Accordingly, in order to prevent such a short caused by contact between the coils disposed or provided on the adjacent boards, the coils 820 may be at least partially coated with an insulator. For example after the coils 820 are disposed or provided on the boards 811 to 815, entire surfaces of both sides of the boards 811 to 815 may be coated with an insulator.

The coils 820 may be disposed or provided on both sides of the respective boards 811 to 815 in a spiral fashion. The term “spiral fashion” used herein may be defined as a curve having a radius that continuously increases or decreases. The coils 820 of all of the boards 811 to 815 may be continuously connected to each other.

Hereinafter, a configuration of the coils, which is intended to increase the number of turns of the coils 820, that is, the number of times the coils are wound, in the plurality of boards 811 to 815 each having a confined size, will be described with reference to the drawings.

FIG. 5 is a schematic plan view showing a flexible circuit board of the displacement sensor shown in FIG. 3, which has been developed. More specifically, based on FIG. 5, an upper part or portion of each of the plurality of boards 811 to 815 may serve as an upper coil pattern of each board, and a lower part or portion of each of the boards 811 to 815 may serve as a lower coil pattern of each board. For the convenience of explanation, two outermost boards among the plurality of boards 811 to 815 may be designated a first board 811 and a fifth board 815, respectively, and the boards disposed or provided between the first board 811 and the fifth board 815 may be designated a second board 812, a third board 813, and a fourth board 814, respectively.

Referring to FIGS. 3 to 5 the plurality of boards 811 to 815 may be continuously stacked in a zigzag fashion by bending the one or more connectors 830, as described above. More specifically, when the plurality of boards 811 to 815 is stacked, the upper portion 811-1 of the first board 811 may face upward, and the lower portion 811-2 of the first board 811 may face downward. The lower portion 812-2 of the second board 812 may face upward and the upper portion 812-1 of the second board 812 may face downward. The upper portion 813-1 of the third board 813 may face upward, and the lower portion 813-2 of the third board 813 may face downward. The upper portion 814-1 of the fourth board 814 may face downward, and the lower portion 814-2 of the fourth board 814 may face upward. Finally, the upper portion 815-1 of the fifth board 815 may face upward, and the lower portion 815-2 of the fifth board 815 may face downward.

Consequently, the lower portion 811-2 of the first board 811 may face the lower portion 812-2 of the second board 812. The upper portion 812-1 of the second board 812 may face the upper portion 813-1 of the third board 813. The lower portion 813-2 of the third board 813 may face the lower portion 814-2 of the fourth board 814. Finally, the upper portion 814-1 of the fourth board 814 may face the upper portion 815-1 of the fifth board 815.

In order to connect the coil 820 disposed or provided in one part or portion of each of the boards 811 to 815 to the coil 820 disposed or provided in the other part or portion of each board, each of the plurality of boards 811 to 815 may be provided with a hole H formed therein. In other words, one end of the coil 820 disposed or provided in one part or portion of each of the boards 811 to 815 may be connected to one end of the coil 820 disposed or provided in the other part or portion of each board through the hole H.

More specifically, each of the boards 811 to 815 may be provided with the hole H at positions corresponding to radially inner ends of the coils 820. The radially inner end of the coil 820 disposed or provided in one part or portion of each of the boards 811 to 815 may be connected to the radially inner end of the coil 820 disposed or provided in the other part or portion of each board through the hole H. For example, the radially inner end of the coil 820 disposed or provided in the upper portion 811-1 of the first board 811 may be connected to the radially inner end of the coil 820 disposed or provided in the lower portion 811 of the first board 811 through the hole H.

When the plurality of boards 811 to 815 is stacked, each of two boards 811 and 815, which are positioned at the outermost layers, may be connected to the adjacent board through a single connector 830, and each of the remaining boards 812, 813, and 814, which are disposed or provided between the two outermost boards 811 and 815, may be connected to the adjacent boards through two connectors 830. Referring to FIG. 5, for example, the first board 811, which is positioned at an uppermost level, may be connected to the second board 812 through a single connector 830, and the fifth board 815, which is positioned at a lowermost level, may be connected to the fourth board 814 through a single connector 830. Each of the second board 812, the third board 813 and the fourth board 814, which are disposed between the first board 811 and the fifth board 815, may be connected to the adjacent boards through two connectors 830.

When the plurality of boards 811 to 815 is stacked, the radially outer end of one of the coils 820, which are respectively disposed or provided in the upper and lower parts or portions of each of the plurality of boards 811 to 815, may be connected to the radially outer end of one of the coils 820, which are respectively disposed or provided in the upper and lower parts or portions of the adjacent board, through a connecting coil 831 disposed or provided in the connector 830. In other words, the radially outer end of one of the coils 820, which are disposed or provided in the upper and lower parts or portions of each of the boards 811 to 815, and the radially outer end of one of the coils, which are disposed or provided in the upper and lower parts or portions of the adjacent board, may be connected to each other through the connecting coil 831 disposed or provided in the connector 830. That is, each of the connecting coils 831 may serve to connect the corresponding adjacent ones of the plurality of boards 811 to 815 to each other.

Referring to FIG. 5, for example, the radially outer end of the coil 820 disposed in the lower portion 811-2 of the first board 811 may be connected to the radially outer end of the coil 820 disposed or provided in the lower portion 812-2 of the second board 812 through the connecting coil 831 disposed or provided in the connector 830. The radially outer end of the coil 820 disposed or provided in the upper portion 812-1 of the second board 812 may be connected to the radially outer end of the coil 820 disposed or provided in the upper portion 813-1 of the third board 813 through the coil 831 disposed or provided in the connector 830. The radially outer end of the coil 820 disposed or provided in the lower portion 813-2 of the third board 813 may be connected to the radially outer end of the coil 820 disposed or provided in the lower portion 814-2 of the fourth board 814 through the coil 831 disposed or provided in the connector 830.

The radially outer end of the coil 820 disposed or provided in the upper portion 814-1 of the fourth board 814 may be connected to the radially outer end of the coil 820 disposed or provided in the upper portion 815-1 of the fifth board 815 through the coil 831 disposed or provided in the connector 830. In this way, according to embodiments, connection between the coils of two adjacent boards may be implemented by means of the connector 830. Accordingly, there is no need for additional holes to connect the coils 820 of the plurality of boards 811 to 815 to each other. In other words, each of the plurality of boards 811 to 815 may be provided with only one hole for connection between the coil provided in the upper portion of the board and the coil disposed in the lower portion of the board. Accordingly, according to embodiments, the number of turns of the coil 820 provided in each of the boards 811 to 815, that is, the number of times the coil is wound, may be increased compared to a case of having a plurality of holes. That is, according to embodiments, by virtue of increasing the number of turns of the coil 820, the sensitivity and accuracy of the displacement sensors 81 and 82 be improved.

The connecting coil 831 may have a mesh or grid shape. In other words, in order to prevent breakage of the connecting coil 831 upon bending of the connector 830, the connecting coil 831 may be configured to have a mesh or grid shape. Accordingly, even if the connecting coil 831, which may be configured to have a grid shape, is partially broken upon bending of the connector 830, it is possible to prevent breakage of the connecting coil 831 and to reliably connect the coils 820 of the adjacent boards 811 to 815 to each other.

In order to accurately control the rotating shaft 120 provided in the compressor 10 based on a signal detected by the displacement sensors 81 and 82, a configuration of the displacement sensors 81 and 81 and control of the magnetic bearings 141 and 142 based on values detected by the displacement sensors 81 and 82 are critical. Hereinafter, a configuration of the displacement sensors 81 and 82 and control of the magnetic bearings 141 and 142 based on values detected by the displacement sensors 81 and 82 accord in to an embodiment will be described with reference to the drawings.

FIG. 6 is a schematic cross-sectional view showing the displacement sensor shown in FIG. 3, which is mounted on a bearing housing of the compressor. FIG. 7 is a block diagram showing a connection relationship between components of the chiller system according to an embodiment.

As described with reference to FIG. 2, the displacement sensors 81 and 82 may include a plurality of displacement sensors disposed or provided in front of and behind the motor 130, and the magnetic bearings 141 and 142 may include the plurality of magnetic bearings 141 and 142 disposed or provided in front of and behind the motor 130. For the convenience of explanation, the displacement sensors 81 and the magnetic bearings 141 will hereinafter be described based on the displacement sensor 81 and the magnetic bearing 141 disposed or provided in front of the motor 130. However, it will be appreciated that the following description may also be applied to the displacement sensor 82 and the magnetic bearing 142 disposed or provided behind the motor 130.

Referring to FIGS. 6 and 7, the bearing housing 140 may be provided with a plurality of the displacement sensors 81. The plurality of displacement sensors 81 may be arranged such that they surround the rotating shaft 120 provided in the compressor 10 and such that they are radially spaced apart from the rotating shaft 120. For example, the plurality of displacement sensors 81 may include a first displacement sensor 81-1, a second displacement sensor 81-2, a third displacement sensor 81-3 and a fourth displacement sensor 81-4. The plurality of displacement sensors 81 may include a first pair of displacement sensors, which may vertically face each other, and a second pair of displacement sensors, which may face each other in a direction perpendicular to an imaginary line I that connects the first pair of displacement sensors to each other, that is, in a horizontal direction.

The first pair of displacement sensors, which may face each other in a vertical direction above and below a horizontal section of the rotating shaft 120, may detect displacement of the rotating shaft 120 in the vertical direction, and the second pair of displacement sensors, which may face each other in the horizontal direction, may detect displacement of the rotating shaft 120 in the horizontal direction. Referring to FIG. 6, for example, the plurality of displacement sensors 81 may include first and third displacement sensors 81-1 and 81-3, which may face each other in the vertical direction above and below the horizontal section of the rotating shaft 120, and second and fourth displacement sensors 81-2 and 81-4, which may face each other in a direction perpendicular to the imaginary line I that connects the first and third displacement sensors 81-1 and 81-3 to each other, that is, in the horizontal direction.

In other words, referring to the X-Y coordinates shown in FIG. 6, the plurality of displacement sensors 81 may include the first pair of the first and third displacement sensors 81-1 and 81-3, which may face each other in the Y-axis direction with respect to the rotating shaft 120, and the second pair of the second and fourth displacement sensors 81-2 and 81-4, which may face each other in the X-axis direction with respect to the rotating shaft 120. The first and third displacement sensors 81-1 and 81-3 may serve to detect vertical displacement of the rotating shaft 120, and the second and fourth displacement sensors 81-2 and 81-4 may be serve to detect horizontal displacement of the rotating shaft 120.

As shown in FIG. 7, for example, the plurality of displacement sensors 81 may be electrically connected to controller C. In other words, the first displacement sensor 81-1, the second displacement sensor 81-2, the third displacement sensor 81-3, and the fourth displacement sensor 81-4 may be electrically connected to the controller C. Consequently, values detected by the first displacement sensor 81-1, the second displacement sensor 81-2, the third displacement sensor 81-3, and the fourth displacement sensor 81-4 may be transmitted to the controller C.

The controller C may determine a position of the rotating shaft 120 in the vertical direction based on a first value, which may be a difference between the values detected by the first pair of displacement sensors 81-1 and 81-3. That is, the first value may indicate the difference between the values detected by the first displacement sensor 81-1 and the third displacement sensor 81-3, which may face each other.

Further, the controller C may determine the position of the rotating shaft 120 in the horizontal direction based on a second value, which may be a difference between values detected by the second pair of the displacement sensors 81-2 and 81-4. That is, the second value may indicate the difference between the values detected by the second displacement sensor 81-2 and the fourth displacement sensor 81-4, which may face each other.

The reason why positional control of the rotating shaft 120 employs the difference between values detected by displacement sensors that face each other, rather than simply values detected by individual displacement sensors, is to implement accurate positional control of the rotating shaft 120 even when a diameter of the rotating shaft 120 varies due to heat or centrifugal force, for example. In other words, when the position of the rotating shaft 120 is controlled based on the difference between values detected by a pair of displacement sensors that faces each other, it is possible to accurately control the position of the rotating shaft even when the diameter of the rotating shaft 120 varies due to heat or centrifugal force, for example. For example, when the difference between values detected by the pair of displacement sensors that faces each other becomes zero, it may be considered that the rotating shaft 120 is positioned at the center in the bearing housing 140.

The bearing housing 140 may be provided with a plurality of the magnetic bearings 141. The plurality of magnetic bearings 141 may surround the rotating shaft 120 and so as to be radially spaced apart from the rotating shaft 120. For example, the plurality of magnetic bearings 141 may include a first magnetic bearing 141-1, a second magnetic bearing 141-2, a third magnetic bearing 141-3, and a fourth magnetic bearing 141-4.

The plurality of magnetic bearings 141 may include a first pair of magnetic bearings, which may face each other in the vertical direction above and below the horizontal section of the rotating shaft 120, and a second pair of magnetic bearings, which may face each other in a direction perpendicular to the imaginary line I that connects the first pair of magnetic bearings to each other, that is, in the horizontal direction. In other words, the plurality of magnetic bearings 141 may be disposed or provided at positions that correspond to the first and second pairs of displacement sensors in a radial direction. For example, the plurality of magnetic bearings may be mounted on the bearing housing 140 in front of or behind the corresponding displacement sensors 81.

In the embodiment shown in FIG. 2, the plurality of magnetic bearings 141 in front of the motor 130 may be disposed or provided in front of the corresponding front displacement sensors 81, and the plurality of magnetic bearings 142 behind the motor 130 may be disposed or provided behind the corresponding rear displacement sensors 82. However, an anteroposterior positional relationship between the magnetic bearings 141, which may be disposed or provided in front of the motor 130, and a front displacement sensor 81, and an anteroposterior positional relationship between the magnetic bearings 142, which may be disposed or provided behind the motor 130, and a rear displacement sensor 82 are not limited to this embodiment.

The first pair of magnetic bearings, which may face each other in the vertical direction, may control displacement of the rotating shaft 120 in the vertical direction, and the second pair of magnetic bearings, which may face each other in the horizontal direction, may control displacement of the rotational shaft 120 in the horizontal direction. Referring to FIG. 6, for example, the plurality of magnetic bearings 141 may include the first and third magnetic bearings 141-1 and 141-3 which may face each other in the vertical direction above and below the horizontal section of the rotating shaft 120, and the second and fourth magnetic bearings 141-2 and 141-4, which may face each other in the direction perpendicular to the imaginary line I that connects the first and third magnetic bearings 141-1 and 141-3 to each other. In other words, referring to the X-Y coordinates shown in FIG. 6, the plurality of magnetic bearings 141 may include a first pair of the first and third magnetic bearings 141-1 and 141-3, which may face each other in the Y-axis direction with respect to the rotating shaft 120, and a second pair of the second and fourth magnetic bearings 141-2 and 142-4, which may face each other in the x-axis direction with respect to the rotating shaft 120. The first pair of the first and third magnetic bearings 141-1 and 141-3 may be configured to control the vertical displacement of the rotating shaft 120, and the second pair of the second and fourth magnetic bearings 141-2 and 142-4 may control the horizontal displacement of the rotating shaft 120.

As shown in FIG. 7, for example, the magnetic bearings 141 may be electrically connected to the controller C. In other words, the first magnetic bearing 141-1, the second magnetic bearing 141-2, the third magnetic bearing 141-3, and the fourth magnetic bearing 141-4 may be independently and electrically connected to the controller C. Accordingly, the controller C may control the magnetic bearings 141 so as to position the rotating shaft 120 at a predetermined position in the bearing housing 140. More specifically, the controller C may control the position of the rotating shaft 120 in the bearing housing 140 in such a way as to receive signals from the plurality of displacement sensors 81, calculate the above-mentioned first and second values, and drive the magnetic bearings 141.

As is apparent from the above description, embodiments disclosed herein provide a compressor and, a chiller system including a compressor, in which sensitivity of displacement sensors disposed or provided around a rotating shaft of the compressor is increased. Further, embodiments disclosed herein provide a compressor including displacement sensors and a chiller system including a compressor, in which the displacement sensors employ flexible circuit boards so as to be more space-efficient. In addition, embodiments disclosed herein provide a compressor and a chiller system including a compressor, which are able to more accurately control a position of a rotating shaft based on a difference between values detected by the displacement sensors provided around the rotating shaft.

Furthermore, embodiments disclosed herein provide a compressor and a chiller system which are able to reduce noise generation by the compressor, to increase an efficiency of the compressor and to prevent breakage of the compressor by accurately controlling the position of the rotating shaft. Accordingly, embodiments disclosed herein are directed to a compressor and a chiller system including a compressor that substantially obviate one or more problems due to limitations and disadvantages of the related art.

Embodiments disclosed herein provide a compressor and a chiller system including a compressor, in which sensitivity of displacement sensors provided around a rotating shaft of the compressor is increased. Embodiments disclosed herein provide a compressor including displacement sensors and a chiller system including a compressor, in which displacement sensors employ flexible circuit boards so as to be more space-efficient.

Embodiments disclosed herein provide a compressor and a chiller system including a compressor, which is able to more accurately control a position of a rotating shaft based on a difference between values detected by displacement sensors provided around a rotating shaft. Embodiments disclosed herein provide a compressor and a chiller system, which is able to reduce noise generated in the compressor, to increase efficiency of the compressor and to prevent breakage of the compressor by accurately controlling a position of a rotating shaft.

Embodiments disclosed herein provide a compressor that may include one or more impellers that draw a refrigerant in an axial direction and compress the refrigerant in a radial direction, a rotating shaft that rotates the impellers, and a displacement sensor that detects displacement of the rotating shaft. The displacement sensor may include a flexible circuit board and coils disposed or provided on both sides of the flexible circuit board. The flexible circuit board may include a plurality of board units or boards, which may be connected to each other via one or more connectors. The plurality of board units may be stacked in a zigzag fashion by bending the one or more connectors.

Each of the coils may be arranged on one of two sides of the board units in a spiral fashion. Each of the board units may have a via hole formed at a position corresponding to a radially inner end of the coil. The radially inner end of the coil disposed or provided on one or a first side of each board unit may be connected to the radially inner end of the coil disposed or provided on the other or a second side of the corresponding board unit through the via hole.

When the plurality of board units is stacked, each of two board units disposed or provided at outermost layers may be connected to an adjacent board unit through a single connector, and each of one or more board units disposed or provided between the two outermost board units, may be connected to the adjacent board units through two connectors. When the plurality of board units is stacked, a radially outer end of each of the coils disposed or provided on both sides of each of the board units may be connected to a radially outer end of one of the coils disposed or provided on both sides of an adjacent board unit through a coil disposed in a corresponding connector.

The coil disposed or provided in the connector may be configured to have a mesh shape. The one or more connectors and the plurality of board units may be integrally formed with each other. Each of the coils may be at least partially coated with an insulator.

The displacement sensor may further include a ferrite core, which may be coupled to the plurality of board units. Each of the plurality of board units may have a coupling hole formed in a center thereof, and the ferrite core may include a coupling protrusion corresponding to the coupling hole. The displacement sensor may detect a radial displacement of the rotating shaft. The displacement sensor may include a plurality of displacement sensors, which may be disposed or provided around the rotating shaft and may be radially spaced apart from the rotating shaft.

The plurality of displacement sensors may include a first pair of displacement sensors, which may be disposed or provided to face each other in a vertical direction above and below a horizontal section of the rotating shaft and a second pair of displacement sensors, which may be disposed or provided to face each other in a direction perpendicular to an imaginary line that connects the first pair of displacement sensors to each other.

A position of the rotating shaft in a vertical direction may be determined by a first value, which may be a difference between values detected by the first pair of displacement sensors, and a position of the rotating shaft in a horizontal direction may be determined by a second value, which may be a difference between values detected by the second pair of displacement sensors.

The compressor may further include a controller, which may be electrically connected to the first pair of displacement sensors and the second pair of displacement sensors. The bearing housing may be provided with magnetic bearings that surround the rotating shaft, and the first pair of displacement sensors and the second pair of displacement sensors may be disposed or provided at positions that radially correspond to positions of the magnetic bearings disposed or provided around the rotating shaft. The controller may control the magnetic bearings such that the rotating shaft may be disposed or provided at a predetermined position in the bearing housing based on the first value and the second value.

Embodiments disclosed herein provide a chiller system that may include a compressor that may include one or more impellers draw a refrigerant in an axial direction and compresses the refrigerant in a radial direction, a rotating shaft that rotates the impellers, and a displacement sensor that detects displacement of the rotating shaft a condenser that exchanges heat between a refrigerant compressed in the compressor and cooling water so as to condense the refrigerant, an expansion valve that expands the refrigerant condensed in the condenser, and an evaporator that exchanges heat between the refrigerant expanded at the expansion valve and cold water so as to evaporate the refrigerant and cool the cold water. The displacement sensor may include a flexible circuit board and coils disposed or provided on both sides of the flexible circuit board. The flexible circuit board may including a plurality of board units which may be connected to each other via one or more connectors.

The plurality of board units may be stacked in a zigzag fashion by bending the one or more connectors. When the plurality of board units is stacked, a radially outer end of each of the coils disposed or provided on both sides of each of the board units may be connected to a radially outer end of the corresponding one of the coils disposed on both sides of an adjacent board unit through a coil disposed or provided in a corresponding connector.

The displacement sensor may include a plurality of displacement sensors, which may be disposed or provided around the rotating shaft and may be radially spaced apart from the rotating shaft. The plurality of displacement sensors y include first pair of displacement sensors, which may be disposed to face each other in a vertical direction above and below a horizontal section of the rotating shaft, and a second pair of displacement sensors, which may be disposed or provided to face each other in a direction perpendicular to an imaginary line that connects the first pair of displacement sensors to each other.

A position of the rotating shaft in the vertical direction may be determined by a first value, which may be a difference between values detected by the first pair of displacement sensors, and a position of the rotating shaft in a horizontal direction may be determined by a second value, which may be a difference between values detected by the second pair of displacement sensors.

The chiller system may further include an air-conditioning unit or air-conditioner that exchanges heat between the cold water cooled at the evaporator and air in an air-conditioning space so as to cool the air in the air-conditioning space.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A compressor comprising: one or more impellers that draws a refrigerant in an axial direction and compresses the refrigerant in a radial direction; a rotating shaft that rotates the one or more impellers; and at least one displacement sensor that detects a displacement of the rotating shaft, wherein the at least one displacement sensor includes a flexible circuit board and coils provided on both sides of the flexible circuit board wherein the flexible circuit board includes a plurality of boards which are connected to each other by one or more connectors.
 2. The compressor according to claim 1, wherein the plurality of boards is stacked in a zigzag fashion by bending the one or more connectors.
 3. The compressor according to claim 2, wherein each of the coils is arranged on one of both sides of the plurality of boards in a spiral fashion, wherein each of the plurality of boards has a hole formed at a position corresponding to a radially inner end of the coil, wherein the radially inner end of the coil provided on a first side of each board is connected to the radially inner end of the coil provided on a second side of the board through the hole.
 4. The compressor according to claim 3, wherein, when the plurality of boards are stacked, each of two boards, which are provided at outermost layers, is connected to an adjacent board by a single connector, and each of one or more boards, which are provided between two outermost boards, is connected to adjacent boards by two connectors.
 5. The compressor according to claim 3, wherein, when the plurality of boards is stacked, a radially outer end of each of the coils provided on both sides of each of the boards is connected to a radially outer end of one of the coils provided on both sides of an adjacent board through a coil provided in a corresponding connector.
 6. The compressor according to claim 5, wherein the coil provided in the connector is configured to have a mesh shape.
 7. The compressor according to claim 1, wherein the one or more connect and the plurality of boards are integrally formed with each other.
 8. The compressor according to claim 1, wherein each of the coils is at least partially coated with an insulator.
 9. The compressor according to claim 1, wherein the at least one displacement sensor includes a ferrite core, which is coupled to the plurality of boards, wherein each of the plurality of boards has a coupling hole formed in a center thereof, and the ferrite core includes a coupling protrusion corresponding to the coupling hole.
 10. The compressor according to claim 1, wherein the at least one displacement sensor detects a radial displacement of the rotating shaft.
 11. The compressor according to claim 10, wherein the at least one displacement sensor includes a plurality of displacement sensors, which is provided around the rotating shaft and is radially spaced apart from the rotating shaft.
 12. The compressor according to claim 11, wherein the plurality of displacement sensors includes a first pair of displacement sensors, which faces each other in a vertical direction above and below the rotating shaft, and a second pair of displacement sensors, which faces each other in a direction perpendicular to an imaginary line that connects the first pair of displacement sensors to each other.
 13. The compressor according to claim 12, wherein a position of the rotating shaft in the vertical direction is determined based on a first values which is a difference between values detected by the first pair of displacement sensors, and a position of the rotating shaft in a horizontal direction is determined by a second value, which is a difference between values detected by the second pair of displacement sensors.
 14. The compressor according to claim 13, further including a controller which is electrically connected to the first pair of displacement sensors and the second pair of displacement sensors, wherein the bearing housing is provided with magnetic bearings that surround the rotating shaft, and the first pair of displacement sensors and the second pair of displacement sensors are provided at positions that radially correspond to positions of the magnetic bearings provided around the rotating shaft, and wherein the controller controls the magnetic bearings such that the rotating shaft is provided at a predetermined position in the bearing housing based on the first value and the second value.
 15. A chiller system including the compressor accordingly to claim
 1. 16. A chiller system, comprising: a compressor including one or more impellers that draws refrigerant in an axial direction and compresses the refrigerant in a radial direction, a rotating shaft that rotates the one or more impellers, and at least one displacement sensor that detects a displacement of the rotating shaft; a condenser that exchanges heat between the refrigerant compressed in the compressor and cooling water so as to condense the refrigerant; an expansion valve that expands the refrigerant condensed in the condenser; and an evaporator that exchanges heat between the refrigerant expanded at the expansion valve and cold water so as to evaporate the refrigerant and to cool the cold water, wherein the at least one displacement sensor includes a flexible circuit board and coils provided on both sides of the flexible circuit board, and wherein the flexible circuit board includes a plurality of boards, which is connected to each other by one or more connectors.
 17. The chiller system according to claim 16, wherein the plurality of boards is stacked in a zigzag fashion by bending the one or more connectors.
 18. The chiller system according to claim 17, wherein, when the plurality of boards is stacked, a radially outer end of each of the coils provided on both sides of each of the plurality of boards is connected to a radially outer end of a corresponding one of the coils provided on both sides of an adjacent board through a coil provided in a corresponding connector.
 19. The chiller system according to claim 16, wherein the at least one displacement sensor includes a plurality of displacement sensors, which is provided around the rotating shaft and is radially spaced apart from the rotating shaft, wherein the plurality of displacement sensors includes a first pair of displacement sensors, which faces each other in a vertical direction above and below the rotating shaft, and a second pair of displacement sensors, which faces each other in a direction perpendicular to an imaginary line that connects the first pair of displacement sensors to each other.
 20. The chiller system according to claim 19, wherein a position of the rotating shaft in the vertical direction is determined based on a first value, which is a difference between values detected by the first pair of displacement sensors, and a position of the rotating shaft in a horizontal direction is determined based on a second value, which is a difference between values detected by the second pair of displacement sensors.
 21. The chiller system according to claim 16, further including an air-conditioner that exchanges heat between the cold water cooled at the evaporator and air in an air-conditioning space so as to cool the air in the air-conditioning space.
 22. A compressor, comprising: one more impellers that draws a refrigerant in an axial direction and compresses the refrigerant in a radial direction; a rotating shaft that rotates the one or more impellers; and a plurality of displacement sensors distributed in pairs around a circumference of the rotating shaft, wherein the pairs of displacement sensors detect a radial displacement of the rotating shaft in a vertical direction and a horizontal direction, respectively.
 23. The compressor according to claim 22, wherein each of the plurality of displacement sensors includes a flexible circuit board and coils provided on both sides of the flexible circuit board.
 24. The compressor according to claim 23, wherein the flexible circuit board includes a plurality of boards which are connected to each other by one or more connectors.
 25. The compressor according to claim 24, wherein the plurality of boards is stacked in a zigzag fashion by bending the one or more connectors.
 26. The compressor according to claim 24, wherein the one or more connectors and the plurality of boards are integrally formed with each other.
 27. The compressor according to claim 22, wherein the radial displacement of the rotating shaft in the vertical direction is determined based on a first value, which is a difference between values detected by a first pair of displacement sensors, and the radial displacement of the rotating shaft in the horizontal direction is determined by a second value, which is a difference between values detected by a second pair of displacement sensors.
 28. A chiller system including the compressor accordingly to claim
 22. 